Container and tear strip key attached thereto



Nov. 30, 1954 H. FRILLMAN 2,

CONTAINER AND TEAR STRIP KEY ATTACHED THERETO Filed April 8, 1952 INVENTOR. MAME/97 FP/z .4 All/V BY/ZZ, 4 1 52 JP FILM/e2 Wad/M A T TOE/VEYS United States Patent CONTAINER AND TEAR STRIP KEY ATTACHED THERETO Lambert H. Frillman, Maywood, Ill., assignor to American Can Company, New York, N. Y., a corporation of New Jersey Application April 8, 1952, Serial No. 281,191 2 Claims. (Cl. 220-52) The present invention relates to a sheet metal tearing strip can having auxiliary parts and to a method of welding the auxiliary parts thereto and has particular reference to a can having an exteriorly located opening key and an interiorly located corrosion retarding disc both of which are welded simultaneously to an end member of the can.

In the packing of certain products, such as meats, the well known tearing strip can is frequently used to facilitate easy opening of the can by the consumer. Opening keys usually are attached to the cans, preferably by welding, for use in removing the tearing strips.

Sheet metal cans commonly are made of tin plate or the like material having an iron base covered with a protective layer of tin or an organic coating or both. The heat required to fuse or weld an opening key to a can is so great that it sometimes causes breaks in the protective layer of tin or organic coating material. When these breaks in the protective coating occur on the inside of the can, the iron base thus exposed, is sometimes attacked by the contents of the can with the result that discoloration of certain products such as meats, fruit juices, beer, etc., takes place when packed in such cans. It is well known that the incorporation of aluminum metal or a suitable alloy of aluminum, or magnesium in the can in electrical connection with the metal of the can and with the contents is effective in eliminating this discoloration. The theory behind this phenomenon is that the aluminum which is a metal higher in the electro-chemical series than the metal of the can functions to protect the metal of the can electrolytically, becoming the anode of a galvanic couple of which the iron and/ or tin of the container is the cathode.

An object of the invention is the provision of a tearing strip can provided with a key for opening the can and a suitable corrosion retarding metal disc to prevent discoloration of the product, the key and the disc being welded to an end member of the can, on opposite sides of the end member and by the same weld spots so as to minimize the exposure of the base metal of the member.

Another object is the provision of a method of attaching these two auxiliary can parts to a can end member or other part in one and the same welding operation.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

Figure 1 is a perspective view of a filled and sealed sheet metal tearing strip can embodying the instant invention; and

Fig. 2 is an enlarged sectional view of a portion of the top end member of the can before attachment thereto, the view being taken substantially along a vertical plane indicated by the lines 2-2 in Fig. 1, showing how the opening key and the disc are welded to the can end member in accordance with the method steps of the invention.

As a preferred or exemplary embodiment of the invention Fig. l of the drawing illustrates a sheet metal tearing strip container or can comprising a square tubular sheet metal body 11 having countersunk panel top and bottom sheet metal end members 12, 13 secured thereto in suitable end seams 14, 15. The can body 11 preferaby is formed with a side seam 16.

Adjacent the top end of the can, the body 11 is formed with a pair of spaced and parallel score lines 17 which extend completely around the body and set off between them a removable tearing strip 18 which includes a tongue 19 projecting beyond the body side seam 16. By tearing out this tearing strip 18, the top end portion of the can is completely separated from the body 11 and may be readily lifted off to remove the contents from the can. This is a conventional tearing strip can.

Removal of the tearing strip 18 preferably is effected by a metal opening key 21 which is attached to the exterior surface of the countersunk panel of the top end member 12. The key 21 preferably comprises a shank 22 having a loop handle 23 at one end and an attaching pad 24 at the opposite end. The shank 22 is provided with an elongated slot 25 for application to the tongue 19 of the tearing strip 18 to wind up and thereby tear out the strip in the usual manner. The attaching pad 24 preferably is provided with a pair of sharp projections 26 (see Fig. 2) to facilitate attachment of the key to the can end by welding. This pad end of the key by way of the projections 26 rests on and is welded to the outer face of a preferably circular raised boss 27 formed in the countersunk panel of the can end.

The raised boss 27 on the outer face of the countersunk panel of the can end 12 provides an oppositely disposed circular recess 28 (see Fig. 2) in the opposite or inner face of the can end. This recess 28 contains a fiat disc 29 of aluminum metal or other suitable metal preferably welded in place to the can end. The recess preferably is of such a depth as to cause the exposed face of the disc to be flush with the inner face of the can end member. The inner face of the end member including the recess preferably is provided with a film 31 of a protective coating material.

Attachment of the key 21 and the disc 29 to the can end member 12 is effected prior to the application of the end member 12 to the can body 11. Hence the flush relation of the disc to the inner face of the end member facilitates handling of these end members without damage to the disc. In like manner the key 21 is protected by being disposed within the countersunk panel of the end member.

When the end member 12 with its key 21 and disc 29 is secured in place on a can body 11, the disc 29 is disposed inside the can and thereby acts in the well known manner to prevent discoloration of the product.

The method of attaching the key 21 and the disc 29 to the can end member 12 comprises the steps of arranging the key in its predetermined place on the outer face of the countersunk panel of the can end and arranging the disc 29 in its place in the recess 28 in the inner face of the can end. In arranging the key 21, its projections 26 are placed in contact with the top or outer face of the boss 27. With the key 21 and the disc 29 in their predetermined places, a welding electrode 33 (Fig. 2) is pressed against the attaching pad 24 of the key 21 and a second oppositely disposed electrode 34 is pressed against the disc 29.

While the electrodes 33, 34 are so pressed toward each other and against the key 21 and the disc 29 to press these auxiliary can parts against opposing faces of the can end member, an electric current is passed between the electrodes and through the engaged metal parts of the pad of the key 21, the disc 29 and the can end 12 to thus fuse or weld these parts together in one and the same operation. This welding together of the auxiliary parts and the can end usually takes place at the projections 26 on the key attaching pad 24 and embed the projections into the can end as best shown in Fig. 2. In the region of the projections 26 a small bare spot or spots free of the coating 31 is left to provide for metal to metal contact between the disc 29 and the inner face of the can end. However, this exposure of the base metal by this break in the continuity of the protective coating 31 is minimized since it is located under the disc 29 and is compensated for by the corrosion retarding action of the disc.

Electric current is passed between the electrodes 33, 34 in any suitable manner such as through an electric circuit which includes a wire 35 (Fig. 2) connecting the electrode 33 with a source of current such as a,

generator 36, a wire 37 connecting the generator with a normally "open switch "38; "and'a' wire 39'com1ectin'g the switch with the electrode 34. Opening and closing of the switch 38 controls the flow of electric current betvvtehen rhe -electrodes and tlre can parts:in eontact there- W1 It isthouglit tha'tth'e inv'ention' and many -of-' its-attendantadvantages'willibe understood fi'om the foregoing description, and it 'w ill be-a parenr that: various -'changes may be made in the' form',construction,and arrangement o'f par ts-of theapparatus mentionedherein and in the steps and tlieir r order: of -accomplishment ot the process described herein, wi'thoute-depar'ting from the'spirit and scope of theirive'ntionwr sacrificing-all -of* its material advantages, the apparatusand p'ro'eess hereiribefore described being-merely:a'prererrea embodiment thereof.

I claim:

-1. A tearing strip cfit'ainer "for-products having metal corrosive characteristics, comprising in combination a metal 'tu'bular body, top and bottom metal 'end-- members securedto said body, 'a filrn of {protective coating 'ma-terial on "theiin'ner sui fac'es--of-" said con'tainer, aremovable tearing strip in 's'aid containerfor use .in opening the. container, a metal opening key for removing said tearing strip, said ke'y having -*projectionswelded to an exterior surface of sii'idcontaiiier, :and a corrosion retarding disc of -metal --electropositive to-the base metal of said container, said -disc overlying said film of protective coatinginateria1and beiiig welded to the inner surface of the container opposite said key projections for :minimizin'g-eirpo'sure of the-base metal-under said film incident to welding=-said oppositelydisposed key and disc to the container and for electrolytically protecting any ofsaid base-metal of thecontairier exposed-through said film-of protective coatingmaterial, the construction-and location of said key and said disc permitting said welding' to *be accomplished sirmiltaneously in a single welding operation;

2. A tearing strip container for products having metal "corrosive characteristics, -coinpri's"mg in -com'binatiom'a metal tubular body, top and bottom metal end members secured to said body, a film of protective coating material on the inner surfaces of said container, a removable tearing strip inqsaidacontainer for use in opening the container, said container having a recess formed in the 'inner'surfacejithercof, a metal 'openingpkey for removing said tearing strip, said key Zhaving projections welded to an exterior surface of said container opposite said recess, and a corrosion retarding disc of metal electropositive tothe :base metal of-said csntetiner, said disc overlying said film of protective coating :material and being disposed in saidrecess and weldedto the container opposite said keyprojectionsfor minimizing exposure of the base metal under said-film incident to welding said oppositely disposed key and disc to the container and for electrolytically protecting any of said base metal of the container :exposedthrough said: film of protective coating material.

References Cited ;.in the1fi1e: ofzthisgpatent UNITED 'STATESiPATENTS Number Name Date 1,754,447 Stollberg Apr; :15, 1.930 1,844,846 Fogarty Feb-.9, 1932 1,958,765 Perkins May '15, 1934 2,014,090 "Schnetzer Sept. 210, 19.35 2,030,906 .Malley ;Feb. 118; 19-356 2,137,623 .Mussey "Nov. 22,.1-"938 2,229,275 Burns :J an. 21', 19.411 2,243,832. -Bohn June'B, 1941 2,478,962 Ziehmer, Jr J-Aug. l6, 1949 2,583,575 vCasson Jan. 29,1952 

